Forced-draft device



Oct. 16, 1928. 1,688,118

c. DUCAS FORCED DRAF T DEVI CE Filed Sept. 1926 VINVENTOR Charles Dflt'fij} b QMJ I ATTORNEY Patented Get. 16, 192 8.

CHARLES DUCAS, OI NEW YORK, N. Y.

FORCED-DRAFT nnvrcn.

Application filed September 1, 1926- Serial No. 132,994.

My present invention relates to an. ini-v provement in forced draft devices known as exhaust or jet nozzles, such as are used for creating artificial or forceddraft in steam boiler fire boxes, and especially adapted to utilization in locomotive boilers.

One of the distinct advantages of my construction, relates to the provision, in a device of this kind, of an annular jet or blast port whereby exhaust steam from the cylinders maybe passed up through the stack of the locomotive to create a forced draft, by jet or aspiration action, through the fire box, and the stream of exhausting steam is directed in a hollow conical form thereby creating a draft of air in a highly efiicient manner. It has beenascertained thatthis form of'hollow annular stream of steam readily entrains a large amount offire-box gases and carries them upward and outwardly through the stack, through its greatly increased area of contact with the gases, by reasonof the'interior and exterior surfaces presented by the hollow annular steam jet, so. formed.

Another advantage relates to the structure of the nozzle itself, in which all of the foregoing features are accomplished by a single, unitary structure, having a minimum number'of required connections to the steam and exhaust end of'the boiler and cylinders, making for ease of manufacture, installment and replacement.

These and other features and capabilities will be'ascertained as the disclosure proceeds and I do not desire to belimited to the details thereof as it is obvious that modifications may be made in the structural details, without departing from the scope of the invention as hereinclaimed.

Fig. 1 is a sectionalview of a conventionalized locomotive boiler showing my device in operative position, and partly in action.

Fig. 2 is a plan view of my device.

Fig. 3 is a sectional. view thereoftaken on the line 33 of Fig. 2, looking in the direction of the arrow; a

Fig. 4; is a lOOtlZOD'LVlGW of my device, and a Fig. 5 is a partial sectional elevation from the front or steam jet end. i

In ordinary installations ofa device of this kind it is customary to place. this device immediately and, axiallyund er the stacks, Fig. 1 which, is a complemental portionof the boiler, generally denoted by B. The boilerandits component parts are obviously shown in conventional form for the purpose of illustration and comprises heating tubes T, which pass through the baffle or head wall B in the usual structural practice.

For the sake of convenience and brevity I have omitted the steam cylinders and connections therefromwhereby the draft creatlng steam is delivered to the draft nozzle, as these are well knownfeatures and are readily understood. a

By referring to Fig.1, my draft or exhaust nozzle, generally denoted by N, is located, preferably, upon a suitable seat, within the boiler and by means of a flange 1 may be bolted or otherwise fastened through the bolt holes 2, Fig. 4 to said seat, not shown, which constitutes the top of the exhaust saddle from the-engine cylinders There is also provided a downwardly formed or combustion deflecting bafiie Y,,

Fig.1, which compels the gases of combustion, as they pass through the heating tubes T, to be deflected downwardly and for wardly about the nozzle N in the direction of the arrows A, around and about-theexhaust nozzle N; this" battle Y is preferably here connected to the nozzle N so as to entirely e11- close anddivide the front end ofthe boiler 7 into two chambers, V the upper and W the lower, and the forward end of theba fiie, is so.

constructed as to support and operatively hold therein a spark arrester screen, as denoted by X, through which, the combustion gases pass, as indicated by the arrows, under the aspiration of the forwardly steam jet 14;. i

By referring to Figs. 3- and 5, it will be noted that substantially at or a little lower moving 3 than, the middle of the nozzle N there is provided onopposite sides two opposingentry ports 3 and 4, respectively thereby bifurcating the nozzle atits interior at this point, and

these interior ports merge by an easy curve into a single central upwardly directedemission port 5. Just below this port and, preferably integral therewithis arranged a steam inlet duct, generally denoted by 6, which terceive thereina valved steam pipe connection from'the boil r, or other controlled pressure source, whereby steam or may be introduced therein to create a starting blast for causing 'a draft up through the stack; may

S, :or be utilized, ordinarily, when the engine is at a standstill, by the opening of a suitable steam controlling valve, not shown.

- For the purpose ofcreati-ng a draft during operationo-f the locomotive, by means of the exhaust steam from thecylinders, an outer nozzle' is provided with two ports 9 and 10. j-at its lower end or 'base 1, these ports being connected tot'he opposite locomotive steam like, as indicated by cylinders, not shown, whereby during the operation oithecylinders, exhaust steam is in termittently introduced into these opposite ports, whence they pass upwardly and merge into a common chamber, generally denoted by ill at the upper end thereof, around and above the ports and 4.

lit the upper end of this outer chamber 11 and suitably and firmly mounted thereon is an annular jet cap 12 which is so proportioned that it lea-vesan annular exhaust steam opening 13 whereby the steam emits there through at high velocity. This steam as it emits upwardly, expands hollow and cone- 7 dotted lines 14 andfit "will be noted that as iti r-eaches the upper end of the stacks that' i t practically fills the central-portion of the stack tothe outer upper ed ges'thereo if and that during such action it willcreate a draft as' previously described.

- The inner jet nozzle 7 creates an upward blast of air or steam, generally denoted by 15, 1 at the dottedlines and this serves the purpose as herein described for creating a draft-when startingthe fire, orwhen the locomotive is standing still.

"It is obvious from the foregoing description-that I have provided a draft creating nozzl-ethat is unitary in its structure. and 1S arrangedso as to increase the area of gas contact with the steam jet as t aspires, and

contracts with the boiler gases.

The increased exhausting efiort 1s accomplished by the structural features of the an nular jet nozzle 12, the annular jet port 18, the interior uprising chamber 5, with its gas inletports 3 and 4, whereby there is added to the outer surface of the steam exhaust jet =14, anfinterior'surface area thereof. This causes added contact areas of gas and steam I and greatly increasesthe draft in the firebox. v 7 Having thusdisclosed'my invention, what Ic'i-ahnistr a 1 means jet cap for the ends oit said central and outer chambers, said cap having a relatively large circular "opening for discharge 0f gases of com'bustionfifrom the central chamber and projectingacross the outlet of said annular steaan chamber sons to leave a narrow annular opening around and adjacent'to said circular opening for discharge'oif steam from the outer chamber at high velocity, passages 0011-. necting said annuiar chamber with engine cylinders appurtenant to the boiler for providing unbroken passage ofstcam from said cylinders to saiidannu'l-ar discharge opening,

the steam discharged from said annular opening being the form of a hollow cone, the gases of combustion being drawn from the boiler chamber through Saidinlet ports of the central chamber by entrainment of said hollowcone of steam and discharged through said circular outlet opening of the central chamber in the form of a column of gases of combustion surrounded by the hollow cone of steam, and a jet located in the axial line or said nozzle at the bottom of said central chamber adjacent to the inlet 'po-rtsthereof and connected tothesteam generating means of the boiler'tor projecting a stream of steam into said chamber whereby the gases of coinbu-stion are drawn through saidports and discharged through said circular outlet in a column of mingled gases and steam tby entrainment of said stream :of steam for providing draftw'hen said engine cylinders are not operating. v

2. a "nozzle, in combination, a base, an inner housing circularwin crosssectiondisposed on said base and forming aicentral chamber havinga pair of oppositelywdisposedintalre ports for gases of combustion, an outer housing disposedaronnd the inner housing and forming an outer chamber having an annular portion around the central chamber above said intake ports and having on sideso'f-the outer chamber opposite'said intake ports of the central chamber oppositely related extensions of theouterchamber ing theend of each of said extensions adjacent said base to the exhaust of an engine cylinder, said extensions and connecting means'providing unbroken passage for steam terminating at said base,-means for connect- 325 "from eachcylinder to said" annular portion 330 of the outer chamber, and an annular jet cap for the ends of said central and outer chambers opposite said base, said cap having a relatively large circular opening for dis- 5 charge of gases of combustion from the cen tral chamber and projecting across the outlet of said annular steam open ng so as to leave a narrow annular opening around and ad acent to said circular opening for discharge of steam from the outer chamber at high 10 velocity.

Signed at New York, in the county of New York and State of New York, this 28th day of August, D. 1926.

CHARLES DUCAS. 

